The invention relates to using multiple serial bus devices with a driver program.
Referring to FIG. 1, for the purpose of electrically capturing an optical image 11, a typical digital camera 12 (of a digital imaging system 21) may include an array of photon sensing pixel sensors 20. During an integration interval, each pixel sensor 20 typically measures the intensity of a portion, or pixel, of a representation of the optical image that is focused (by optics of the camera 12) onto the pixel sensors 20. At the expiration of the integration interval, each sensor 20 typically indicates (via an analog voltage, for example) an intensity of light of the pixel.
The camera 12 typically processes the indications from the pixel sensors 20 to form a frame of data which digitally represents the captured image. The frame may be transferred via a serial bus 15 (a Universal Serial Bus (USB), for example) to a computer 14 for viewing or stored in a flash memory of the camera 12. During video operations, the camera 12 may capture several optical images in succession and furnish several frames of data to the computer 34, each of which indicates one of the captured images. The computer 14 may then use the frames to recreate the captured video on a display 9.
The computer 14 typically executes driver programs to communicate with devices that are coupled to the serial bus 15. Quite often, the driver program may be designed for communication with only one bus device. For example, a camera driver program 17 may be designed to cause the computer 14 to communicate with one camera that is coupled to the serial bus 15. A difficulty may arise when an additional camera 18 is coupled to the bus 15, as more than one camera may exceed the driver program's capabilities.
Thus, there is a continuing need for a system that accommodates the use of multiple serial bus devices with a single device-driver program.